Support RPL_NOTPIC and 005

Move the irc callbacks into the cpp file

Support a trusted SHA1 fingerprint to be configured for each IRC server

Support multi-prefix

See http://ircv3.net/specs/extensions/multi-prefix-3.1.html
ref #3103

Use references instead of raw pointer, to store the “parent” object

In Bridge and IrcClient

Add the outgoing_bind option

Lets the admin choose a local address to bind each outgoing (IRC) socket.

Provide an adhoc option to let user pass the cert verif for some IRC servers

Fix the initial IRC nickname (was using realname, by mistake)

Implement a basic webirc support

See https://kiwiirc.com/docs/webirc

fix #3135

Fix the double sending of the USER command

Fix some trivial issues reported by cppcheck

Introduce the realname_from_jid option

When set to true, the realname and username are extracted (by default) from
the user’s JID

fix #3136

Provide the “realname_customization” option

ref #3136

The realname is also saved as an IrcClient member

Provide username and realname IRC server options

Used in the USER command when connecting to the IRC server, instead of the
first nick.

fix #3028

Connection may be closed from our side too

Add a field (in the configure form) to specifiy an after-connect IRC command

Provide Ports and TLS Ports IRC-server ad-hoc options

This let any user choose which ports to use when connecting to the IRC
server. This also lets the user choose whether or not to force TLS usage (by
setting no non-TLS port).

fix #2731

Send a PASS IRC command if the “pass” config is sot by a user, on an IRC server

fix #3068

Trivial cleanup in irc_client.cpp